Flow control valve utilizing sonic nozzle

Abstract

A flow control valve for a semiconductor manufacturing process, which valve utilizes a pressure sensor between the flow control valve and a subsequent sonic nozzle to detect the gas pressure which is fed back to the valve to control the flow through the valve.

What is claimed: 
     
       1. A flow control valve comprising a closed fluid passage having an exit disposed in a base and a valve member fixed on the base, wherein a sonic nozzle is disposed at the exit side of the valve member within the closed fluid passage, and   wherein a gas pressure in the upstream side of the sonic nozzle is detected by a pressure sensor between the valve member and the sonic nozzle and fed back to the valve member to control the flow rate through the sonic nozzle in the closed fluid passage.   
     
     
       2. A flow control valve as claimed in claim 1, wherein the valve member is a solenoid valve. 
     
     
       3. A flow control valve as claimed in claim 1, wherein the valve member is a piezo actuator. 
     
     
       4. A flow control valve as claimed in claim 1 wherein the pressure sensor includes a means to produce a stable flow rate control through the sonic nozzle in the closed fluid passage. 
     
     
       5. A flow control valve as claimed in claim 1 wherein the pressure sensor is also connected to a remote pressure monitor means for also monitoring the pressure upstream of the sonic nozzle in the closed fluid passage. 
     
     
       6. A flow control valve as claimed in claim 1 wherein the pressure sensor is the sole means to control the flow rate through the sonic nozzle in the closed fluid passage. 
     
     
       7. A flow control valve as claimed in claim 1 wherein the valve member, sonic nozzle, and pressure sensor are unitary with the base. 
     
     
       8. A flow control valve as claimed in claim 1 wherein there is an adaptor intermediate of the sonic nozzle and the base. 
     
     
       9. A flow control valve comprising a closed fluid passage having an inlet and an exit disposed in a base and a valve member fixed on the base, wherein a sonic nozzle is disposed at the exit side of the valve member within the closed fluid passage between the inlet and the exit,   wherein a gas pressure on the upstream side of the sonic nozzle is detected by the pressure sensor between the valve member and the sonic nozzle and fed back to the valve member to control the flow rate through the sonic nozzle in the closed fluid passage, and   the pressure sensor is the sole means to control the flow rate through the sonic nozzle in the closed fluid passage.   
     
     
       10. A flow control valve as claimed in claim 9 wherein the valve member is a solenoid valve. 
     
     
       11. A flow control valve as claimed in claim 9 wherein the valve member is a piezo actuator. 
     
     
       12. A flow control valve as claimed in claim 9 wherein the pressure sensor includes a means to produce a stable flow rate control through the closed fluid passage. 
     
     
       13. A flow control valve as claimed in claim 9 wherein the pressure sensor is also connected to a remote pressure monitor means for also monitoring the pressure in the closed fluid passage. 
     
     
       14. A flow control valve as claimed in claim 9 wherein the valve member, sonic nozzle, and pressure sensor are unitary with the base. 
     
     
       15. A flow control valve as claimed in claim 9 wherein there is an adaptor intermediate of the sonic nozzle and the base.